M8 Glasgow - J21-22

J21 consists of west facing ramps, and J22 is only east
facing - so the motorway between them consists of four separate 3-lane
carriageways to eliminate weaving. J22 is the more impressive of the
two junctions, with left hand exits from the two westbound carriageways
and merges from left and from right of the two eastbound
carriageways. J21 consists of simple nearside ramps to the street.

The outer carriageways, which currently serve only the J21 entry and
exit, were built to link directly to the south flank of the Inner Ring
Road. They're now planned be used for the M74 extension - and this
description is written on the assumption that that scheme will proceed.

Looking west towards J22.

Between J20 and J22, the M8 has four carriageways, the inner
carriageways from the Kingston Bridge and the outer carriageways from the
M74 and local traffic. At J22, the M8 and M77 divide, and the
junction allows eight flows - four westbound and four eastbound.

View east from J22. The inner carriageways only serve the Kingston
Bridge, and this will not change with the M74 extension

The first of the two J21 exits visible in the distance on the left, and
the merge from the matching J21 entry at far right.

The outer carriageways currently only serves the eastbound J21 exits
and the westbound entries, but were intended to form the start of the
south flank of the Inner Ring Road, and will become part of the M74.

View west towards J22 showing the double exit at left and the two merges
at right.

Both the westbound carriageways have a left exit to the M77.

The outer carriageway has a lane drop at the exit, followed by a
reduction to a single lane before merging with the inner
carriageway. The inner carriageway continues with three lanes
throughout.

It's expected both through carriageways will be modified to two lanes
only, with a tiger-tail merge.

Looking north along the pedestrian overbridge over the junction: The
Kinning Park Underground station on the left, and in the distance is the
Stobcross crane on the far side of the Clyde.

As with parts of the M8 north of the river, the footbridges over the
motorway here follow graceful curves and spirals. There are no steps
on the ramps, so they're fully accessible to cycles and disabled.

Vandalism isn't so much of a problem with improved CCTV coverage and a
rapid response from local police when problems are detected.

16 lanes of traffic at this point!

Looking east from the middle of J22: The other footbridge is visible
just beyond the gantry sign in the foreground, with the Kinning Park
Underground station to the left.

Parallel merges of M77 and M8 traffic.

The bulk of the traffic here is currently headed for the Kingston
Bridge, but this will change once the M74 Extension is completed and
linked to the outer carriageways.

Closer look at the M77/M8 merge. The two lanes at left are from
M8, then three lanes from M77, and finally two lanes from M8.

Looking west, the three ramps for the M77 traffic are clearly seen, the
two at the left for westbound traffic and the one in the foreground for
eastbound traffic splitting into two carriageways to join the M8 traffic
rising on either side of it.

The lane drop here has been improved by converting it to a tiger-tail
merge.

Prior to this changethere was a simple lane drop further back on the
sliproad, with a single lane at this point joining the M8. The
tiger-tail merge allows better balance between the two flows.

The eastbound M8 also has a lane drop shortly before the merge - This
could easily be improved with a lane drop at the previous exit. This
may well happen when the M74 works are completed.

Westbound: M74 climbing to M77, M74 to M8, M8 climbing to M77, and M8 to
M8.

Eastbound: M8 to M8, M77 to M8 and M74 and (out of picture) M8 to M74.

View northeast showing the double diverge of M8 and M77.

The double diverge seen from the road. The M77 exits to the left
on both carriageways.

And one picture of the M8 much further west. This is the White
Cart Viaduct, as seen from the top deck of the new car park at Glasgow
Airport.